Snow modelling in JULES

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Snow modelling in JULES Richard Essery
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Snow in MOSES
Increases surface albedo a aveg (asnow
aveg)(1 e-S/5) Decreases surface
roughness z0 max z0veg - 410-4 S, 510-4
Decreases thermal conductivity of
surface Lumped with surface (10 cm) soil
layer Constant density (250 kgm-2) and thermal
conductivity (0.265 Wm-1K-1) No storage or
refreezing of liquid water in snow No
representation of snow under vegetation
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Tile model structure
T1, Q1, U1
Hv
rv
Hs
rs
z1
Tv
Ts
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MOSES2 tiles ERA40 tiles (Essery et al.
2003) (van den Hurk et al. 2000) Broadlef
trees Bare soil Needleleaf trees High
vegetation C3 grass Low vegetation C4
grass High vegetation, snow beneath Shrubs Sn
ow on low vegetation Urban Interception
layer Inland water Sea-ice Bare soil Open
water Land ice JULES generalized tiles?
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PILPS2e
Bowling et al. 2002. Global Planet. Change, 38,
1-30.
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PILPS2e
Bowling et al. 2002. Global Planet. Change, 38,
1-30.
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Dual-source model structure
T1, Q1, U1
H
ra
Hc
Tc
Ta
z1
rc
Hs
rs
Ts
Blyth et al. 1999. HESS, 3, 71-84.